Recently there have been various glasses-type video display devices in which video displayed on a display device such as a Liquid Crystal Display (LCD) is observed as a virtual image enlarged through an optical system having an eyepiece, a half mirror, or the like. The glasses-type video display devices are called a head-mounted display. For example, WO2004/061519A1 (Patent Document 1) discloses a head-mounted display.
Many video display devices are configured in such a way that they are worn on a face while wrapped around a head. Video display devices are mainly divided into a binocular type in which the video display system is formed at positions corresponding to eyes and a monocular type in which the video display system is formed at a position corresponding to one of the right and left eyes. Usually the head-mounted display includes a display unit which displays video and a headphone which supplies sound. The headphone which is of a kind of the output device is widely used as a sound output device for listening to music.
Manipulation components (such as a switch) used to manipulate the head-mounted display can be provided in a control box or the like which is formed independently of a main body unit to be mounted on the head. On the other hand, there has been made an attempt to attach the manipulation components to a headphone unit or a headphone retaining unit of the head-mounted display main body unit to be mounted on the head.
Patent Document 1: WO2004/061519A1
Patent Document 2: Japanese Patent Application Laid-Open No. 2004-233776